Interpolymers of aliphatic conjugated dienes and blocked vinyl isocyanates

ABSTRACT

This invention is directed to interpolymers of aliphatic conjugated dienes and blocked vinyl isocyanates which are particularly useful for forming self-anchoring coatings on various substrates and for the preparation of cross-linked or cross-linkable molding resins.

United States Patent Rubens et al. [451 Sept. 26, 1972 INTERPOLYMERS OFALIPHATIC Referelllles Cited sfgiggzg y gfifg AND BLOCKED UNITED STATESPATENTS Inventors: Louis C. Rubens James T K. 2,326,287 8/1943 Coffman..260/85.7 b991- of Mlch' 48640 Primary Examiner-Donald E. Czaja [73]Assignee: The Do v Chemical Company, Mid- Assistant Examiner-M. 1. Welshr Attorney-Griswold & Burdick, Ronald G. Brokkens [22] Filed: Nov. 301970 and Albm R. Lmdstrom [2l] Appl. No.: 93,884 5 ABSTRACT Thisinvention is directed to interpolymers of aliphatic [52] ffi iz 5conjugated dienes and blocked vinyl isocyanates R which are particularlyuseful for forming self-anchor- 51 lm. Cl. ..C08g 22/32 ns coatings onvarious Substrates and for the Prepara- 8 Field of Search 5 BB, 75 TBtion of cross-linked or cross-linkable molding resins.

3 Claims, No Drawings INTERPOLYMERS OF ALIPHATIC CONJUGATED DIENES ANDBLOCKED VINYL ISOCYANATI'B BACKGROUND the pronounced moisturesensitivity of such interpolymers resulting from the reactivity of theisocyanate groups.

lt is the primary object of the present invention to prepareinterpolymers composed of predominant amounts of aliphatic conjugateddienes and minor amounts of blocked vinyl isocyanates wherein'the NCOgroups of the vinyl isocyanate will be available for cross-linking withother polymer materials to form molding resins of desirably high impactstrength and/or for the formation of curable protective or adhesivecoatings on various substrates.

Other and related objects will become evident from the followingspecification and claims.

SUMMARY OF THE INVENTION The above and related objects are attainedaccording to the present invention by preparation of interpolymersconsisting essentially of l) at least about 75 weight percent of analiphatic conjugated diene having from about four to carbon atoms, (2)from 1 to about weight percent of a blocked vinyl isocyanate and (3) theremainder being one or more copolymerizable ethylenically unsaturatedmonomers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The aliphatic conjugated dienesused herein have, in general, from four to 10 carbon atoms .and arerepresented by 1,3-butadiene, isoprene, 2-methyl-l,3-- butadiene,2,3-dimethyl-l,3-butadiene, piperylene, 2- neopentyl-l,3-butadiene andother hydrocarbon homologs of 1,3-butadiene such as the straightandbranched-chain pentadienes, and the straight-and branched-chainhexadienes. Especially preferred are l,3-butadiene and isoprene.

Blocked vinyl isocyanates are described by F. H. Saunders and K. C.Frisch, in Polyurethanes Chemistry and Technology, Part I Chemistry,Volume 16 High Polymers, lnterscience, 1966, page 120; and in an articleby G. R. Griffin and L. F. Willwerth, entitled The Thermal Dissociationof Blocked Toluene Diisocyanates, Product Research and Development,Industrial Engineering and Chemistry, Volume 1, number 4, Dec. 1962.

where Y is I Q Q- B'@* flr m o,m,p

0 I 01111 vp distributed up to pentasubstituted; and

here R is alkyl or aryl.

In addition to the required classes of monomers specified above, theremay be used small amounts of other ethylenically unsaturated monomers asTypical such other monomers are the monovinylidene {aromatic compoundsof the benzene series such as styrene and substituted styrenes includingalphamethylstyrene, p-vinyltoluene, o-vinyltoluene, p-tert.-butylstyrene, ar-ethylstyrene, ar-dimethylstyrene, methoxystyrene,ethoxystyrene, cyanostyrene, monochlorostyrene, dichlorostyrene,monobromostyrene and other halostyrenes. Other useful monomers includethe acrylonitriles such as acrylonitrile and methacrylonitrile, thealkyl esters of an acrylic acid in which the alkyl portion has from oneto 12 carbon atoms, such as methyl acrylate, methyl methacrylate, ethylacrylate, ethyl methacrylate, npropylacrylate, n-propyl methacrylate,isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butylmethacrylate, isobutyl acrylate, isobutyl methacrylate, Z-ethylhexylacrylate, 2-ethylhexyl methacrylate, noetyl acrylate, n-octylmethacrylate, n-decyl methacrylate, and dodecyl methacrylate;ethylenically unsaturated esters of saturated carboxylic acids such asvinyl acetate and vinyl propionate; the ethylenically unsaturatedketones such as methyl isopropenyl ketone; and the hydroxyl-containingalkyl esters of a,/3--ethyleni- .cally unsaturated carboxylic acids suchas B--hydroxyethyl acrylate, B-hydroxylpropyl acrylate, )8--hydrox-.yethyl methacrylate, B-hydroxypropyl methacrylate, 4- hydroxybutylacrylate, 4-hydroxybutyl methacrylate and S-hydroxyamyl methacrylate.

The copolymerized monomers in the interpolymers are present in amount,based on total interpolymer Illustrative of the blocked vinylisocyanates which, 7

weight of (l) at least about weight percent of I aliphatic conjugateddiene, (2) from about 1 to about 15 weight percent of said blocked vinylisocyanate and .(3) the remainder being one or more ethylenicallyunsaturated comonomer.

The monomers may be copolymerized by any known method to form theinterpolymers useful for the present invention. For example, thepolymerization :reaction may be conducted in aqueous emulsionscontaining a catalyst, Typical of such catalysts are the "water-solubleper-compounds, mixtures of water-soluble and monomer-solubleper-compounds, and other compounds having similar decompositionmechanisms such as 2,2'-azobisisobutyronitrile; and in the presence ofwell known emulsifying and/or dispersing agents. Alternatively, theinterpolymers may be prepared by polymerization of the monomericcomponents in bulk without added diluent, or the monomers may be reactedin appropriate organic solvent reaction media.

While there is no critical order of addition (if the various componentsof the monomeric mixture to be polymerized, a convenient manner ofcarrying out the process is to mix the preformed blocked" vinylisocyanate with the remaining monomers in an aqueous medium containingthe catalyst. The various components of the monomeric mixture to bepolymerized can also be conveniently premixed and added to the aqueousmedium containing the catalyst.

The so-formed interpolymers may be advantageously utilized as coatingmaterials in the form of aqueous dispersion or solvent solutions toprovide transparent, continuous protective or adhesive coatings onsubstrates such as wood, concrete, metal and paper, upon curing suchcoatings at a temperature sufi'icient to unblock the isocyanate groups.Further, such interpolymers may be utilized as molding materials whereinthe prescribed interpolymer is molded with another polymeric material,e.g., styrene--hydroxyethylacrylate or hydroxyterminated polyester toprovide high impact materials.

The practice of this invention, as well as the benefits and advantagesthat accrue therefrom, are illustrated in the following example whereall parts and percentages are by weight, unless otherwise specified.

EXAMPLE A. Preparation of P-chlorophenyl Vinylcarbamate l5 Gms. ofp-chlorophenyl was dissolved in 150 ml. of anhydrous ether and 50 mg.Nal-l added. Thereafter, l6 ml. of vinyl isocyanate was slowly added andthe ether evaporated leaving a white solid which was washed with diluteNaOH and then with water. The washed product was then dried overnight atroom temperature under vacuum to form a product having a melting pointof 131 C. B. Preparation of a Copolymer of Butadiene and P- chlorophenylVinylcarbamate 51.4 Gms. (0.95 mole) of anhydrous butadiene and 9.5grns. (0.05 mole) of the p-chlorophenyl vinylcarbamate was dissolved in100 cc of distilled acetone in a citrate bottle and 0.5 gm. ofazobisisobutyronitrile was added. The resulting solution was permittedto polymerize for a period of 72 hours at 70 C in-a Bendix Roto waterbath. 17.5 Gms. (30 percent conversion) of a whitish rubbery solid wasobtained. The nuclear magnetic resonance (NMR) spectrum of the copolymerin perchloroethylene indicated a structure of the followmg:

\ l. NH 1-4 H l 25 mole 55 mole mole a molecule of the polymer.Elemental analysis:

:72. :.9%N:.%. 8. util i za t i ozi 0 f the polymer of (B) as a CoatingMaterial l.6 Gms. of the herein described copolymer was dissolved in 6cc of tetrahydrofuran and coatings were made from the solution on asteel Q panel.

Coatings which were not subsequently baked were characterized by apowderlike, rough surface an did not adhere to the panel. By way ofcomparison, coatings which were heated at 160 C under vacuum for 10minutes (to regenerate the isocyanate functionalities) became clear andwere characterized by a forward and reverse impact of 10 in./lb.(Gardner impact tester).

By way of further comparison, coatings similarly prepared using acopolymer of butadiene and vinyl isocyanate (prepared essentially asdescribed in (B) above) failed to adhere to the metal panel.

What is claimed is:

1. interpolymers consisting essentially of l) at least about weightpercent of an aliphatic conjugated diene having from about 4 to 10carbon atoms and (2) from 1 to about 15 weight percent of a blockedvinyl isocyanate and (3) the remainder being one or more copolymerizableethylenically unsaturated monomers.

2. The interpolymers of claim 1 wherein said blocked vinyl isocyanate isselected from the group consisting of the materials having thestructure:

l lp 3. The interpolymers of claim 2 wherein said aliphatic conjugateddiene is butadiene and said blocked vinyl isocyanate is p-chlorophenylvinylcarbamate.

2. The interpolymers of claim 1 wherein said blocked vinyl isocyanate isselected from the group consisting of the materials having thestructure:
 3. The interpolymers of claim 2 wherein said aliphaticconjugated diene is butadiene and said blocked vinyl isocyanate isp-chlorophenyl vinylcarbamate.